She has the design (which) she is admired for by her colleague.
= She has the design for which she is admired by her colleague. (which不可省)
This carpet (which) you are walking on is no longer ours.
=This carpet on which you are walking is no longer ours. (which不可省)
The hotel, which you will stay in, is famous.
=The hotel, in which you will stay, is famous.
固定搭配动词词组（如look after, fill in, look for, take care of等通常不可拆开）中的介词则不可提前
Your book is one of those which I'll go through.
The boy whom I spoke to is a nice person. 与我讲话的男孩子是个不错的人。
= The boy to whom I spoke is a nice person. （whom不可省）
The retailer, whom I purchased my laptop from, is an old man. 那个零售商是个老人，他卖给我笔记本电脑。
= The retailer, from whom I purchased my laptop, is an old man. （whom不可省）
固定动词词组（如look after, fill in）中的介词则不可提前
He is one of the boys whom I look after.
3. whose 对应先行词是事物时，whose+名词 = the + 名词 + of which
His death, whose cause is unknown, surprises us. 他那不知原因的的死亡令我们惊讶。
= His death, the cause of which is unknown, surprises us.
I shall never forget the day when (on which) we first met.
He came at a time when (at which) we were badly in need of help.
The school where (in/at which) they are working is not far.
That isn’t the hotel where (at which) she stayed when she was in London.
He didn’t give the reason why (for which) he came so early.
The reason why (for which) your letter was returned is that I don’t live there any more.
5.One, some, any, none, all, both, several, many, most, neither, either等词、数词、分数或百分比与of whom或of which连
He has five children, two of whom are abroad.
We have three books, none of which is/are interesting.